posted on 2024-11-01, 10:51authored byHelmut Hugel, Neale Jackson
Theoretical [1] and experimental observations to explain the molecular origins of fluorocarbon hydrophobicity suggest that the hydrophobicity of a fluorocarbon, whether the interaction with water is as solute or as surface, is due to its 'fatness'. In solution, the extra work of cavity formation to accommodate a fluorocarbon, compared to a hydrocarbon, is not offset by enhanced energetic interactions with water. The enhanced hydrophobicity of fluorinated surfaces arises because fluorocarbons pack less densely on surfaces leading to poorer van der Waals interactions with water. The interaction of water with a hydrophobic solute/surface is primarily a function of van der Waals interactions and is substantially independent of electrostatic interactions. This independence is primarily due to the strong tendency of water at room temperature to maintain its hydrogen bonding network structure at an interface lacking hydrophilic sites.